COMP: Ensure library paths used for BundleFixup are valid

The helper macro "_fixup_paths_append" is now used consistently to append
path to the "libs_path" variable.

Let's also note the following updates:

 - CMAKE_RUNTIME_OUTPUT_DIRECTORY is not used anymore, instead
${Slicer_BUILD_DIR}/@Slicer_BIN_DIR@ is used.

 - Path "@Slicer_BINARY_DIR@/@Slicer_QtPlugins_DIR@" is not considered
anymore since it didn't exist in the build tree. Instead, the plugin path
are composed using "${Slicer_BUILD_DIR}/@Slicer_BIN_DIR@"
COMP: Do now explicitly fixup CLI shared library

Considering that (1) CLI shared lirbary are dependency
of CLI executable and (2) CLI executable are already discovered by the
fixup mechanism. There are no need to use canidate pattern for CLI
shared library.
COMP: Simplify expression used in gp_item_default_embedded_path_override.
COMP: Remove hack forcing CMAKE_INSTALL_NAME_TOOL to be empty

In commit r21242 [1], CMAKE_INSTALL_NAME_TOOL has been disabled to ensure
the "gp_item_default_embedded_path_override" function could match
library that are expected to go in specific folders like "cli-modules",
"qt-loadable-modules", [...]. By disabling CMAKE_INSTALL_NAME_TOOL,
the match was possible using full path to each one of the
direct dependencies of a given library.

This approach saw its limitation when trying to have CLI executable
installed in "path/to/Contents/cli-modules" and the shared library copied
into "path/to/Contents/lib/Slicer-4.2/cli-modules". Indeed, the shared
library were systematically copied along side the executable in addition
to the the one existing in the "path/to/Contents/lib/Slicer-4.2/cli-modules"
directory.

This commit doesn't do the match based on the full path embedded in the
library, instead it globs for the expected library in the build tree and
then check if a given item name match the list of library "globed" in the
associated directory.

[1] http://viewvc.slicer.org/viewvc.cgi/Slicer4?view=revision&revision=21242